Effects of foot orthoses: How important is the practitioner?

Foot orthoses (FO) are commonly used in the treatment of numerous lower limb problems, pains and injuries. Whilst many studies report their positive effects, and most practitioners would confirm those findings, the available information appears to be anecdotal. As such, the exact mechanisms in which FO work are not fully understood. Therefore, a need exists to study the influence of the inter-practitioner variability in the assessment of orthoses performance. This investigation is central to the understanding of the performance variations in custom-made foot orthoses (CFO). Eleven practitioners took part in the study. Each practitioner completed a clinical assessment of one subject, after which a pair of foot orthoses was manufactured based on casts of the subject's feet using a neutral non-weight bearing plaster cast. Ten trials per condition were recorded during which kinematic and kinetic data were collected. CFO did not have any systematic significant effects (p<0.05) on any kinetic except for the right-leg peak active force. In addition, systematic kinematic effects could be observed mainly for the sagittal plane for forefoot-to-hindfoot and hindfoot-to-tibia peak angles. The results from this study demonstrate that inter-practitioner variability is a major factor in orthotic intervention in treating a single patient and for a specific pathology. It is therefore strongly recommended to use caution when drawing general conclusions from research studies using custommade foot orthoses. The results suggest that CFO effects can differ between limbs. More importantly, their effects are also practitioner-dependant. Great caution should be used when comparing studies on CFO with different practitioners as conclusions could vastly differ.